Web drive and web processing controls for web processing machines

ABSTRACT

A web drive and web processing controls for web processing machines which include a synchronous torque booster whose input rotation is derived from the web spaced near the storage roll via a web-driven idler roller and whose output rotation positively drives web advancing rollers and the web processing rollers or other processing means, thereby maintaining a constant controlled tension on the web in the processing region.

United States Patent 1191 Hutzenlaub 11 Sept. 18, 1973 [54] WEB DRIVE AND WEB PROCESSING 3,085,457 4/1963 Fischer 226/36 X CON S R WEB PROCESSING 3,165,056 1/1965 Heatley.... 226/30 X MACHINES 3,381,868 5/1968 Vogeler 226/42 X Inventor: Armin S. P. Hutzenlaub, Wiehl,

Germany Assignee: Erwin Kampf Maschinenfabrik,

Wiehl, Germany Filed: June 23, 1972 Appl. No.: 265,425

Foreign Application Priority Data June 24, 1971 Germany P 21 31 446.5

US. Cl. 226/42, 242/7553 Int. Cl B65h 17/20 Field of Search 226/30, 31, 36, 40, 226/42; 242/7553 References Cited UNITED STATES PATENTS 11/1939 Douglas 242 7553 x Primary Examiner-Richard A. Schacher Attorney-Leo A. Rosetta et al.

[57] ABSTRACT A web drive and web processing controls for web processing machines which include a synchronous torque booster whose input rotation is derived from the web spaced near the storage roll via a web-driven idler roller and whose output rotation positively drives web advancing rollers and the web processing rollers or other processing means, thereby maintaining a constant controlled tension on the web in the processing re- 4 Claims, 1 Drawing, Figure WEB DRIVE AND WEB PROCESSING CONTROLS FOR WEB PROCESSING MACHINES BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to web drives and in particular to controls for the synchronous drive of web advancing means and of web processing means in the web processing stations of web processing devices.

2. Description of the Prior Art The field of application of the present invention includes such web processing devices as web slicing and web cutting machines with drum-type cutters, web winding machines, web unwinding machines, web stretching machines, web printing machines and many others. The webs thus processed are generally in the form of a continuous thin and flexible band or film of either metal, synthetic material or other materials of a similar nature.

Such processing machines generally have a driven supply roll and a variable-torque storage roll or storage rolls, around which the web is wound with an approximately constant circumferential tension. The web is thus subjected to a certain longitudinal tension between the supply roll and the storage roll, which tension is variably augmented or diminished through friction, processing resistance and other forces in the processing device, and these in turn are influenced by the processing speed. One known approach to a stabiliza tion of the web tension suggests the use of a variablespeed web drive by means of which the friction of the processing roller and other processing resistances, such as a cutting resistance for example, may be compensated for. This solution includes a DC-motor. which responds to the speed of web advance. The drive is controlled through the residual friction'between the processing roller and the advancing web. It is not possible, however, to adjust this type of auxiliary variable-speed drive in such a way that direction and size of its drive assistance provide an accurate compensation for the varying mechanical resistances in the web run, specially in high speed processing machines. A residual force of variable size remains between the web and the processing rollers and either pulls the web forward or tends to retard it.

The problem of varying web tensions is especially critical where thin and stretchable webs or films are being processed and where it is desirable to use supply rolls and storage rolls of large capacity with a wide diameter range. The rotary inertia inherent in suchheavy rolls further adds to the difficulties in controlling the web tension at high operating speeds. For some very sensitive webs, however, it is highly desirable to maintain the web tension during processing at a constant minimal value. In other cases it is necessary to prevent any difference in speed between the surface of the processing rollers and the web, especially such cumulative errors as are caused by slippage. In many cases it is advantageous to have both a constant web tension and a synchronous web advance without slippage.

SUMMARY OF THE INVENTION It is a primary objection of the present invention to provide a web drive for web processing machines in which the web advancing means and web processing means are driven synchronously and by means of which the web tenson in the processing station, or stations, is maintained at a constant value.

The invention proposes to attain the above objective by suggesting a web drive and web drive controls which include a torque booster with synchronously rotating input and ouput shafts, the input motion being provided by a web-driven idler roller which engages the web near the web-advancing storage roll, the output motion being used to positively drive the web processing rollers or other processing means in the web processing station and to positively advance the web from the supply roll to the web processing station at exactly the same lineal web speed at which the web moves over the idler roller.

Th web-driven idler roller is preferably so arranged that the web partially wraps around the roller, thereby giving an accurate indication by its circumferential speed at the lineal web speed.

This same circumferential speed is instantly reproduced with any desirable force at the web advancing rollers and at the wb processing rollers in the web pro cessing station.

In addition to providing a variable speed signal the roller also conveniently provides the integral value of the speed signal, viz the total web advance, so as to eliminate the possibility of any cumulative errorin web roller is preferably arranged near, or in pre-loaded com advance. Thus, the device of the invention provides for an accurately synchronous drive connection between the web advancing means and the web processing means so that the web tension in the region of the web processing station, i.e. between the idler roller and the web-advancing roller remains unaffected by variations in the web tension outside this region, such as for example, by variations in the overall web tension resulting from the drives of the supply and storage rolls. This feature is particularly important for sensitive webs.

In a further refinement of the invention it is suggested 'to connect the idler roller via a tachometer shaft with the input of the torque booster, the output shaft of the latter being in positive drive connection with the web advancing roller andweb processing means. The idler tact, wth the storage roll.

The torque booster is preferably a known hydraulic torque booster with synchronously rotating input and output shafts. The movement of the input shaft of the hydraulic torque booster controls the intake opening of a hydraulic valve in the booster and thereby causes the output shaft to move in unison with the input motion. This hydraulic booster is so designed that the phase deviation (lag or advance) between input shaft and output shaft does not exceed a predetermined design value, for example one angular degree. Consequently, there cannot occur any greater angular deviation between the idler roller and the booster-driven rollers than the above design value. Nor is it possible that this phase deviation may increase above the design value in the long run. Thus, the maximum phase deviation is so small that it can easily be sustained by the web length within the controlled web region, and its operative effects can safely be neglected.

BRIEF DESCRIPTION OF THE DRAWING Other objectives and advantages will become more apparent from the following detailed description when taken together with the accompanying drawing which illustrates, by way of an example, a preferred embodiment of the invention in which the FIGURE illustrates in a schematic representation a web processing device with a web slicing station and a web drive embodying the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawing the device of the invention is used in conjunction with a web slicing staton of which only a simplified schematic representation is given. Lkewise, the web drive elements themselves are shown only schematically. All stationary structural elements and many other known design details have been eliminated for reasons of simplicity.

The web supply unit 1 of the device includes a supply roll 2 from which a continuous web 3 is unwound. This supply unit may for example include, as shown, a hydraulic drive motor 4 which is driven by a hydraulic pump 5 via two pressure lines. These elements are not being claimed as novel parts of the invention. Within the processing machine are consecutively arranged the rollers 6, 7, 8 and 9, as well as a slicing roll 10 with a counter roller 11. From the processing station 10, 11 web 3 reaches a storage unit 12 which includes a storage roll 13 and an idler roll 14. The storage unit is similarly driven by a hydraulic motor 15 receiving its pressure from a pump 16. This drive is arranged to provide a substantially constant circumferential pull on the storage roll 13.

The idler roller 14 is so arranged that it engages the web 3 over a substantial angle of its circumference so as to assure that its circumferential speed is the same as the web speed. The idler roller 14 drives to tachometer shaft 17 which is connected to the input shaft 18 of a hydraulic booster 19 by means of mechanical transmission elements. To the booster motor 19 is connected a hydraulic pressure line 20. The booster 19 is so arranged that the rotation of the input shaft 18 opens a valve passage through which the supply of pressure fluid is adjusted. The entering fluid drives the booster output shaft 21 so as to rotate in the direction of valve closing, thereby causing output shaft 21 to follow shaft 18 in a rigorously synchronous motion. The output shaft 2] drives the web advancing roller 8 and the slicing roller 10 via transmission shafts 22 and 23, respectively, by means of intermediate transmission elements. The synchronous drive of these two rollers assures a constant minimal tension on the web region between roller 8 and idler roller 14.

The above-described drive controls provide a web drive in which, except for a minimal phase deviation limited to a predetermined design value, the rollers 8 and 10 have the same circumferential speed as the idler roller 14.

The invention thus makes it possible to positively drive any number of rollers within a web processing machine in synchronous response to the lineal web speed in the web region between the processing station and the driven storage roll. This also means that the web passing through the processing station or stations has a lineal speed which is the same as the circumferential speed of the processing roller so that any slippage or friction effect between web 3 and cutting roller 10, for example, is Obviated.

The invention also permit a deliberate adjustment of different circumferential speeds at different rollers in cases where this is desirable, as for example when the web is to be stretched. This result is obtainable by merely changing the mechanical transmission elements of the torque booster 19 accordingly to obtain the desired speed ratio.

I claim;

1. A web drive for web advancing means comprising in combination:

a web supply roll and a web storage roll as part of the web processing machine;

means for driving at least the web storage roll to wind the web around the roll;

means for processing the web in a processing station located between the supply and storage rolls;

means for advancing the web from the supply roll toward the processing station;

means for sensing the lineal web speed at a point adjacent the storage roll; and

a torque booster responsive to said sensing means for driving the processing means and the advancing means at a speed equal to the lineal web speed as sensed by the sensing means.

2. A drive as defined in claim 1, wherein:

the sensing means is in the form of an idler roller which engages the web near the storage roll with frictional contact over a substantial portion of the idler roller circumference, the idler roller being operationally linked to the torque booster to provide a controlling input therefor.

3. A drive asv defined in claim 2, wherein:

the torque booster is a synchronous hydraulic torque booster with an input shaft and an output shaft, the idler roller being mechanically linked to the booster input shaft via-positive transmission means, the web processing means and web advancing means being likewise mechanically linked to the booster output shaft to be driven thereby.

4. A drive as defined in claim 2, wherein:

the torque booster, the processing means, the advancing means, and the sensing means are so arranged relative to one another that the circumferential speed of the processing means and of the advancing means is the same as the lineal web speed sensed by the sensing means. 

1. A web drive for web advancing means comprising in combination: a web supply roll and a web storage roll as part of the web processing machine; means for driving at least the web storage roll to wind the web around the roll; means for processing the web in a processing station located between the supply and storage rolls; means for advancing the web from the supply roll toward the processing station; means for sensing the lineal web speed at a point adjacent the storage roll; and a torque booster responsive to said sensing means for driving the processing means and the advancing means at a speed equal to the lineal web speed as sensed by the sensing means.
 2. A drive as defined in claim 1, wherein: the sensing means is in the form of an idler roller which engages the web near the storage roll with frictional contact over a substantial portion of the idleR roller circumference, the idler roller being operationally linked to the torque booster to provide a controlling input therefor.
 3. A drive as defined in claim 2, wherein: the torque booster is a synchronous hydraulic torque booster with an input shaft and an output shaft, the idler roller being mechanically linked to the booster input shaft via positive transmission means, the web processing means and web advancing means being likewise mechanically linked to the booster output shaft to be driven thereby.
 4. A drive as defined in claim 2, wherein: the torque booster, the processing means, the advancing means, and the sensing means are so arranged relative to one another that the circumferential speed of the processing means and of the advancing means is the same as the lineal web speed sensed by the sensing means. 